Ra Pharmaceuticals’ macrocyclic peptide inhibitor of complement component 5 is expected to enter phase 3 of its development in the latter half of 2019 after success in a phase 2 trial of its potential in myasthenia gravis.

By: Matt Hoffman

Published: September 10, 2019

Doug Treco, PhD

According to an announcement from Ra Pharmaceuticals, the FDA has granted an orphan drug designation to the company’s investigational generalized myasthenia gravis treatment zilucoplan.1

“gMG is a chronic and debilitating neuromuscular disease that affects more than 60,000 patients in the U.S. who have limited treatment options,” said Doug Treco, PhD, president and CEO, Ra Pharma. “We’ve designed zilucoplan, a macrocyclic peptide inhibitor of C5, as an easy-to-use, self-administered subcutaneous treatment option to address the underlying cause of gMG through targeted complement control.”

“With site activations underway, we are on track to initiate our single, pivotal, 12-week, phase 3 trial of zilucoplan for the treatment of gMG in the second half of this year,” Treco said.

Additionally, in the open-label extension period (98% retention; n = 43), the higher dose group compared to the placebo group (the 0.3 mg/kg dose remained as such [n = 15] while the placebo patients switched [n = 14]). The change from baseline in QMG through Week 24 was significant for both the original treatment arm (P <.0001) and the original placebo arm (P = .01). This was similarly true for both groups, respectively, for Week 24 change in MG-ADL scores (treatment arm, P <.0001; placebo arm, P = .0004).

James F. Howard, MD, Distinguished Professor of Neuromuscular Disease, chief, Neuromuscular Disorders Section, University of North Carolina School of Medicine, at AAN 2019, explained that the therapy is designed to ultimately prevent the formation and assemblage of the membrane attack complex in myasthenia gravis, and last December noted that zilucoplan has the potential to become the first convenient, self-administered, complement inhibitor expanding access for patients living with the chronic, debilitating, neuromuscular disease that is myasthenia gravis.2